His longest-lived contribution to Doctor Who was in changing the TARDIS console room set. Although Mike Kelt had designed and delivered The Five Doctors' new console, Thornton fought for and won the right to redesign the rest of the set. He made the walls more angular, more three dimensional, and, most importantly, individually matched to a particular side of the console. Thus, the whole set became very easy to assemble, since the console could only occupy one spot relative to the walls. (REF: The Fifth Doctor Handbook) This effectively solved the major design problem of the TARDIS console room set that designers had been gradually trying to ameliorate since Peter Brachacki's first, highly complicated set design for An Unearthly Child.